干旱胁迫对云南松种子萌发及渗透调节物质的影响

为探索云南松种子萌发对干旱胁迫的响应,采用不同质量浓度的聚乙二醇(PEG-6000)模拟干旱胁迫进行发芽试验,并测定芽苗的胚根、胚轴长度。结果表明:低浓度的PEG-6000(5%)能促进种子萌发,种子发芽率、日均发芽率、发芽指数均达到最大;而随着PEG-6000浓度的升高种子发芽受到限制,各项发芽指标均呈下降趋势;随着干旱胁迫的增加,云南松种子的胚根长度呈现先上升后下降的趋势,而胚轴长度则呈下降趋势。可溶性糖、脯氨酸含量随着PEG-6000浓度的上升而增加,可能是云南松在水分胁迫下的主要渗透调节物质。

Effect of Drought Stress on Seed Germination and Osmotic Regulating Substances of Pinus yunnanensis

The germination test of Pinus yunnanensis seeds was conducted under artificial drought stress treated with different mass concentration of polyethylene glycol(PEG-6000) in order to explore the effect of drought stress on the seed germination by measuring the radicle length and hypocotyl length of the young seedlings.The results showed that the seed germination was promoted under the low suitable PEG mass concentration.The germination rate,the average daily germination rate and the germination index all reached the peak values under the condition with 5% of PEG-6000 mass concentration.However,the values of P.yunnanensis seed germination indexes declined along with the increment of PEG mass concentration.With the development of water stress(with the increase of concentration of PEG-6000),the length of hypocotyls was decreased gradually,whereas the radicle length increased firstly and then decreased.These results indicated that the seed of Pinus yunnanensis germination were inhibited under the high PEG mass concentration.The contents of soluble sugar and proline increased along with the increment of PEG-6000 concentration,indicating that they were the main osmotic regulating substances in the course of P.yunnanensis seed germination under drought stress.